Toggle bolt latch



July 28, 1959 B. w. HENRICHS I 2,896,751

TOGGLE BOLT LATCH Fi led Nov. 16, 1956 islllllllli INVENTOR. 852N420 w.Alene/ms By 6W ATTOZ/VEKS nited States TOGGLE BOLT LATCH Bernard W.Henrichs, Northridge, Calif., assignor to Clark Hartwell, doing businessunder the name oi. lalrtweli Aviation Supply Company, Los Angeles,

aif.

Application November 16, 1956, Serial No. 622,578 2 Claims. (Cl.189--35)This invention relates to toggle bolt latches, and in. cluded in theobjects of this invention are:

First, to provide a toggle bolt latch which is particularly adapted forexternally flush installation in a contoured structure, such as anaircraft wing, fuselage, or appendage, so that when in its closedposition the latch is completely flush with the surrounding structure.

Second, to provide a toggle bolt latch which provides free movement ofthe latch handle between its flush position and a manually accessibleposition so that when desired the latch may be readily operated.

Third, to provide a latch of this type wherein loads imposed on thelatching element when in its locked position are resisted by a lever andstop means and directly transmitted to the mounting. frame structure,the operating handle being so varranged as to be essentially free ofsuch loads.

Fourth, to provide a particularly compact latch capable of securelylatching component structures under conditions of excessive loads, suchas are encountered by supersonic aircraft.

With the above and other objects in view, as may appear hereinafter,reference is directed to the accompanying drawings in which:

Figure 1 is a side view of the latch in its latching position,indicating by dotted lines the free travel of the handle member andindicating fragmentarily and by broken lines the outline of thestructure in which the latch is mounted;

Fig. 2 is a bottom view of the latch structure;

Figs. 3, 4 and arejtransverse sectional views through 3-3, 4-4, 55,respectively, of Fig. 1;

Fig. 6 is a side view of the latch similar to Fig. 1, but showing thelatch in its open position and indicating friagmentarily and by brokenlines adjacent portions of the structure in which the latch is mounted.

The toggle bolt latch includes a pair of side plates 1 which are joinedby a pair of journal bushings 2 and 3 to form a frame structure. Thejournal bushings are tubular to receive mounting bolts 4 for attachmentto the adjacent structure in any suitable manner, not indicated.

Pivotally mounted on the journal bushing 2 is a pair of toggle latcharms 5 which are separated on the bushing and held adjacent the sideplates 1 by a sleeve 6. The extremities of the toggle latch arms 5 arejoined by a latch pin 7.

Mounted on the journal bushing 3 is a pair of lever members 8 spaced bya sleeve 9. The lever members are pivoted intermediate their ends toform arms 10 which are joined through a journal pin 11 to one end of alink 12, the other end of which is connected by a journal pin 13 to thetoggle latch arms 5. The link member 12 is located in the space betweenthe pairs of lever members 8 and toggle latch arms 5.

The remaining arms 14 of the lever members 8 move.to and from engagementwith a stop pin 15, so located that when the arms 14 engage the stop pin2,896,751 Patented July 28, 1959 the axis of the journal pin 11 occupiesa slightly off center position relative to the axis of the journal bushing 3 and the journal pin 13. In such position, the latch pin 7 andthe extremities of the toggle latch arms 5 are locked in positionagainst any loads that may be imposed thereon.

A handle 16 is provided which may be formed of sheet metal andchannel-shape in cross section, thus comprising side flanges 17 and 18connected by a cross web 19. The side flanges 17 are journaled near oneend of the handle on the journal bushing 3. Their extremities areprovided with arcuate slots 20 which fit over the extremities of thejournal pin 11, so that the handle 16 is capable of moving the journalpin 11 but is capable of free motion determined by the length of theslots 20.

The handle 16 extends longitudinally a substantial distance from theside plates 1, the web. 19 projecting beyond the side flanges 1'7 and18. At this extremity the web 19 is provided with a screw aperture 21which receives a screw or other suitable fastening device, not shown,for the purpose of securing the handle to a surrounding structure.

A spring 22 is wrapped about the sleeve 9 and bears between the handleweb 19 and stop pin 15 so as to urgethe handle toward the limit of itsfree motion, indicated by the dotted line position thereof in Fig. 1.

()peration of the toggle bolt latch is as follows:

The latch is intended to be mounted in a contoured structure, such as anaircraft fuselage or wing, or appendage. It is essential that the web ofthe handle 16 be substantially flush with the surrounding structure; forthat reason the side flanges 17 and 18 may not be identical butmay bevaried in construction, so that the transverse surface of the web 19'may be angularly related to the remaining elements of the latch andconform to the surrounding structure, as indicated best in Figs. 3, 4,and 5. Also the handle may be longitudinally curved. The shape and formof the handle may vary considerably without affecting its operativerelationship with the other elements of the latch.

The toggle latch arms 5 may also vary in length and shape so as toengage hooks, such as that designated A in Fig. 6, or other elements,companion to the latch pin 7. When the latch is in its closed oroperating position, the toggle latch arms 5 are extended and the latchpin 7 is in engagement with an appropriate companion element.

The link 12 is so disposed that the journal pin 11 is slightly pastcenter with respect to the journal bushing 3 and journal pin 13 with thearms 14 of the lever members 3 bearing against the stop pin 15. In suchposition it is impossible to move the toggle latch arms 5 by engagementwith their extremities of any non-descructive force. Under suchconditions no load is imposed on the handle 16. However, the extremityof the handle is secured by a suitable screw or other fastening device,not shown.

When it is desired to open the latch, the screw or fastening deviceretaining the handle 16 is disconnected, whereupon the spring 22 urgesthe handle to a manually accessible position, such as the dotted lineposition shown in Fig. 1. The handle may then be moved manually to thesolid line position shown in Fig. 6. This movement causes the ends ofthe slot 20 to engage the journal pin 11 and move the journal pinclockwise, as shown in the drawings, from the position shown in Fig. 1to the position shown in Fig. 6. In so doing, the link 12 pivots thetoggle latch arms '5 in a clockwise direction, as viewed in thedrawings, so as to disengage the latch pin 7 from its companion element.To return the latch to its locking position, the movement of the handle16 is reversed.

It should be noted that while the latch, when in its closed position,normally imposes no load on the handle 16, should there be acounter-clockwiseload imposed on the link 12 to cause-it to pivot aboutits journal pin 13, such movement is resisted by the handle 16 and thefastening device which connects the handle to the surrounding structure.

While a particular embodiment of this invention has been shown anddescribed, it is not intended to limit the same to the exact details ofthe construction set forth, and it embraces such changes, modifications,and equivalents of the parts and their formation and arrangement as comewithin the purview of the appended claims.

What is claimed is:

1. A toggle bolt latch, comprising: a mounting frame adapted for fixedinstallation in a surrounding structure; a handle lever having a handleend and an operating end, said handle lever disposed within said frameand fulcrumed about a first fixed axis intermediate its ends between aposition flush with said structure and an angular position wherein saidhandle end extends from said structure and the operating end isdepressed into said structure; a toggle element journaled in said frameabout a second fixed axis; a lever member journaled with said handlelever about said first fixed axis and extending to said operating endthereof; a link member joining s'aid lever member and toggle element formoving said toggle element between an extended and a retracted positionon movement of said lever member and link member; and a lost motionconnection between said lever member and said handle lever to permitlimited free movement of said said mounting frame including a pair ofside plates, a pair of spaced journals extending between said sideplates and defining first and second fixed axes, and a stop alsoextending between said plates spaced from the side of the first axisjournal remote from the second fixed axis journal; a toggle latch leverpivotally mounted at one end on said second fixed axis journal andmovable between a latching position, wherein the extended end of saidtoggle latch lever is spaced from the side of said second axis journalremote from the first axis journal and an angularly related freeposition; a stop lever pivotally mounted on said first axis journalhaving an arm engaging said stop whensaid stop lever is in a positioncorresponding to the latching position of said latch lever; a linkpivotally joining said latch lever and stop lever, said link beingconnected to the end of said stop lever remote from said stop engagingarm and to said latch lever inter mediate its ends, the pivotalconnection between said link and stop lever adapted to occupy apredetermined overcenter position with respect to its pivotal connectionwith said latch lever and said first axis journal when said latch leveris in its latching position and said stop lever arm is in engagementwith said stop; and a handle lever pivotally mounted intermediate itsends on said first axis and including an arm having a lost motion slotcoinciding with the connection between said link and stop lever topermit limited free movement of said handle lever.

References Cited in the file of this patent UNITED STATES PATENTS2,610,880 Gayner et a1. Sept. 16, 1952 2,750,217 Landholt June 12, 1956FOREIGN PATENTS 622,197 Germany Nov. 22, 1935

